I have a many to many relationship that seems to work ok, except when I try and remove a User object. When I remove a User object by calling delete (using the Spring HibernateTemplate object) it removes not only the User but all the groups assigned to that user and all the users assigned to those groups.

What I want is if I delete a User it should delete the user and any associations to groups but the groups and other users should remain. I'm really new to Hibernate so I'm sure I'm just missing something simple but it's been driving me crazy.

The mapping is below:

User:
<class name="Users" table="USERS">
<meta attribute="sync-DAO">false</meta>
<id name="Id" type="java.lang.Long" column="USERID">
<generator class="identity"/>
</id>
<property name="Username" column="USERNAME" type="string" not-null="true" length="128" />
<property name="Password" column="PASSWORD" type="string" not-null="true" length="32" />
<property name="Firstname" column="FIRSTNAME" type="string" not-null="false" length="128" />
<property name="Lastname" column="LASTNAME" type="string" not-null="false" length="128" />
<property name="Customerid" column="CUSTOMERID" type="java.lang.Long" not-null="true" length="19" />
<property name="Shipid" column="SHIPID" type="java.lang.Long" not-null="true" length="19" />
<property name="Canadian" column="CANADIAN" type="string" not-null="false" length="1" />
<property name="Email" column="EMAIL" type="string" not-null="false" length="128" />
<!-- inverse end -->
<set name="groups" table="USERSGROUPS" lazy="false" cascade="save-update">
<key column="USERID"/>
<many-to-many class="com.coastdist.domain.Groups" column="GROUPID"/>
</set>
<!--
<set name="shipids" table="SHIPIDS">
<key column="USERID"/>
<element type="string" column="SHIPID"/>
</set>
-->
</class>

Group:
<class name="Groups" table="GROUPS" mutable="false">
<meta attribute="sync-DAO">false</meta>
<id name="Id" type="java.lang.Long" column="GROUPID">
<generator class="identity"/>
</id>
<property name="Groupname" column="GROUPNAME" type="string" not-null="true" length="128" />
<property name="Description" column="DESCRIPTION" type="string" not-null="false" length="254" />
<set name="users" table="USERSGROUPS" lazy="false" inverse="true" cascade="all">
<key column="GROUPID"/>
<many-to-many class="com.coastdist.domain.Users" column="USERID"/>
</set>
</class>

Not sure if this is related but do you need that 'inverse="true"' in your group to users mapping? I thought that was used for one-to-many relationships.

I believe it's needed to determine which side of the mapping is the authoritative, although I'm going off of documentation and the Hibernate book. I have not fully tested it. I'm so unfamiliar with many of the different options I'm not sure if it's truly needed.

That being said, I think I found my problem. It turns out I misunderstood the cascade options. Turns out I only need 'save-update' instead of all. Changing it to save-update fixed the problem.

hi, i have also faced same problem iam giving u 2 suggestions not a solution because iam also not sure ok

1)<set name="users" table="USERSGROUPS" lazy="false" inverse="true" cascade="all">

delete cacade="all" attribute in ur set tag ok i think this will work

y because cascade="all" means it deletes/updates/saves on every operation of parent including all of its child objects so any where cascade="all" is there just delete it or make it cascade="save-update"

2)in ur data base go to fields of that table and make it set no action for ondelete cascade option

hi, i have also faced same problem iam giving u 2 suggestions not a solution because iam also not sure ok

1)<set name="users" table="USERSGROUPS" lazy="false" inverse="true" cascade="all">

delete cacade="all" attribute in ur set tag ok i think this will work

y because cascade="all" means it deletes/updates/saves on every operation of parent including all of its child objects so any where cascade="all" is there just delete it or make it cascade="save-update"

2)in ur data base go to fields of that table and make it set no action for ondelete cascade option